1. Field of the Invention
The present invention relates to a controller.
2. Description of Related Art
A coordinate measuring machine or a machine tool has been known in which a moving mechanism has a plurality of moving axes for moving a probe for measurement, a tool or the like. Such a coordinate measuring machine or a machine tool includes a controller for controlling the moving mechanism based on a position command value.
When the controller controls the moving mechanism, an error between the position command value and a position of the moving mechanism (hereinafter referred to as a route error) may be caused by difference in response characteristics of the respective moving axes.
As a typical control system for reducing such a route error, a feedforward control system including a predetermined compensator has been known (for example, see Document 1: Fujino Yoshikazu, Kyura Nobuhiro “MOTION CONTROL—Practical Mechatronics” Sangyo-Tosho, 1996, Pages 135 to 140).
Typically, when the moving speed of the moving mechanism is increased, the response characteristics of the respective moving axes are changed depending on the moving speed.
However, in the control system disclosed in Document 1, since a value of the compensator is constant, the compensator cannot follow the change of the response characteristics of the respective moving axes while the moving mechanism moves at high speed. Thus, the route error cannot be sufficiently reduced.